The ability to detect and identify sodium leaks in an operating liquid metal fast breeder reactor is considered essential in preventing catastrophic failures from occurring. One commercially available instrument which meets this need is the Westinghouse Sodium Ionization Detector which is described in detail in U.S. Pat. Nos. 4,047,101, entitled, "Filament For Alkali Metal Ionization Detector", and 4,117,396, entitled, "Sensor For Thermally Ionizable Particles And/Or Vapors", both of which are assigned to the assignee of the present invention and incorporated herein by reference. Alkali ion sources are also described in an article entitled, "Duofilament Alkali Ion Source", American Journal of Physics, 47, 290 (1979).
Typically, the detectors are monitored in a control room which is remote from the breaker reactor facility. The detectors require removal from the reactor facility for periodic maintenance and calibration. The efficient use of the detectors could be significantly enhanced if a technique were provided for the in-situ calibration of the detector.